1. Field of the Invention
The present invention relates to a storage system.
2. Description of the Related Art
A storage system comprises one or more storage devices which are used by a plurality of host computers (hereafter “host”), for example. Each host and storage device are connected by an inter-connection device, such as a fiber channel switch and a hub.
A storage device is also called a disk array device or a storage sub-system, for example, and is comprised of many disk drives laid out in an array. The storage device provides a storage area based on RAID (Redundant Array of Independent Disks), for example. On the physical storage area of each disk drive, a logical volume (logical device), which is a logical storage area, is created. And a host, such as a server, can read/write desired data by issuing a write command or read command in a predetermined format to the storage device.
The HBA (Host Bus Adapter) installed on the host is connected to a fiber channel adapter of the storage device via a switch. The host accesses a logical volume via the fiber channel adapter and reads/writes data in block units.
A system, wherein an integrated management mechanism for integratedly controlling an SAN (Storage Area network) is installed and access between a host and storage device is systematically managed by this integrated management mechanism, was proposed (Japanese Patent Application Laid-Open No. 2002-63063).
Access to SAN is managed by the technology written about in the above document. However with this technology the configuration change of a SAN cannot be known, although this configuration changes constantly in order to handle the increases in the data volume to be managed. For example, such devices as switches and hubs are added and replaced when necessary, and a route to connect the storage device and host changes as well.
Also the user of the SAN can download driver software and firmware from the web site of a vendor, for example. The user can also update the HBA and switch when necessary, so the SAN is constantly changed by updating as well.
In this way, the configuration of the SAN is changed from the initial configuration at construction as time passes, so it is difficult to accurately know the configuration of the SAN. In other words, it is difficult to know the connection environment, such as the type of HBA the storage device is connected to, and the type of switch through which the storage device is connected.
If a communication failure occurs to a SAN when the connection environment is unknown, the system administrator and the maintenance engineer must first know the configuration of the SAN, which means that it takes time to specify the location and the cause of the failure generation, and operability, until failure recovery, drops.
Also the storage system is a system product where various information processing elements, such as a host, HBA, switch and storage device, are combined in a complicated way, and each element has various types respectively. And “compatibility” issues exist with the connection of each element. For example, even if no problem occurs when a certain type of switch and a certain type of HBA are combined, a problem may occur if one of the switch and the HBA is changed to a different type.
Therefore for the construction of the storage system, the system is designed considering the compatibility of each element. The designer of the storage system selects a combination for which stable operation is verified, out of the different combinations of elements, and determines the system configuration.
However as mentioned above, the initial configuration where the connection capability of each element is considered, which gradually changes by the change of hardware and software upgrading by the user. And the installation of unverified software for an HBA and a switch by the user, for example, may cause unexpected problems. However the configuration of the storage system at this point has been changed from the initial configuration, and it takes time to accurately know the latest connection environment of the storage system.